نشریه پژوهش های شیمی
سال پنجم شماره 1 (پیاپی 8، بهار و تابستان 1401)

In the present work, oxidation of alcohols with hydrogen peroxide catalyzed by a poly(N-heterocyclic carbene) containing palladium id reported. In this manner, the nano silica particles were functionalized with 3-chloropropyl bromide. Then this functionalized silica nanoparticles were reacted with imidazole, pentaerythrithol tetrabromide, and 1-methyl imidazole, respectively. Finally, this nano material was reacted with PdCl2 to obtain a (PdII-NHCs)n@nSiO2. after, synthesis, this dendiritic polymer was characterized by different analytical techniques. This material was used as an efficient catalyst for oxidation of benzylic alcohols with hydrogen peroxide. In this manner, the reaction parameters such as catalyst amount and kind of solvent was optimized. all reactions were carried out at room temperature and the corresponding aldehydes were obtained in high yields. The mentioned catalyst is of high activity and reusability in the oxidation reactions and reused several times withous significant loss of its catalytic activity. On the other hand, only small amount of Pd was leached in the two first runs.

The maim elements of chromite ore were deduced by X-ray fluorescence (XRF) after collection and grinding. The presence of irregular designs in the form of cavities with size of 50 to 200 micrometers and sometimes nanometers in the structure of this catalyst using solid surface morphology with SEM and TEM electron micrograph scanning was confirmed. In a one-pot three component reaction of diver's aromatic aldehydes, barbituric acid and urea or thiourea, pyrimidopyrimidine (5 , 6 –dihydro – 5 – aryl pyrimido [4 , 5 - d] pyrimidine – 2 , 4 , 7 (1H , 3H , 8H ) - trione) heterocyclic products were prepared in the presence of chromite ore as natural catalyst. There was no need for the column purification of the products in these reactions. Moreover, this methodology offered several advantages such as good yields, simple procedure and simple purification steps. Using water as solvent made the process environmentally and economically benign.

In this study, porous catalysts based on CuO were synthesized using templates of 3D cubic mesoporous silica-type (KIT-6) and copper nitrate as CuO source via nanocasting strategy and nitrate combustion method. Silica templates with a carbon layer on inner structure (KIT-6@C) or deposited on graphene sheets (KIT06@C/G) were prepared through calecination and carbonization of primery surfactans amd graphen oxides in inert atmosphere. The morphology, elemental analysis and structural properties of the templates and catalysts were characterized by means of X-ray diffraction, energy-dispersive X-ray spectroscopy, scaning electron and transmission electron microscopy and nitrogen adsorption–desorption (BET) techniques. The findings indicated that the cubic structure formed in templates and the resulting catalysts have monoclinic crystalline structure and pure of CuO and to some extent, have negative replica structures of cubic silica template. The results of BET for m-CuO@C/G showed that the catalyst has porous structure with some disordered regions, which constructes from meso and macro pores with specific surface area 50.0 m2 g-1 and averaged pores size 4.8 nm. The catalytic activity of m-CuO@C/G towards thermal decomposition of ammonium perchlorate (AP) was investigated by technique of differential scanning calorimetry. With the addition of 2 and 5 wt% of m-CuO@C/G catalyst, the temperature of high decomposition temperature of AP was reduced by 82.6 and 88.5 °C, and the values of their specific heat releases for AP decomposition were increased 2 (820 J g-1) and 2.5 (1085 J g-1) folds of that for pure AP, respectively.

This research represents a theoretical study on the ligands derived from O-phenylenediamine and salicylaldehyde and their complexes with Zn2+ using B3LYP/6-311++G(d,p) and M06-2X/6-311++G(d,p) computational levels. the effect of substituents on the electronic and physicochemical properties of the thirteen complexes obtained with various electron-donating and electron- withdrawing substituted schiff base ( X: NO2, NH2, OCH3, H, F, Cl, Br, CN, OH, N(Me)2, CHO, CH3, CF3) and Zinc cation was investigated. The amounts of the charge transfer, interaction energy, formation enthalpy, Gibbs free energy, structural parameters and geometric properties were perdicted. The result show that the interaction between Zn2+ and ligands increases with the increase of electron-donating nature of substituents on the para position of the phenolic ring of the ligands. Since B3LYP resulted in more accurate results in comparison with M06-2X, then the B3LYP method was applied to the next calculations (NBO, AIM). According to the calculated interaction energies, the order of stability of the complexes was found to be as follows: LN(Me)2Zn > LNH2Zn > LOCH3Zn > LCH3Zn > LOHZn > LHZn> LBrZn > LClZn > LFZn > LCHOZn > LCF3Zn > LCNZn> LNO2Zn.

By developing nanotechnology, nanocarriers, for example, carbon nanotubes (SWCNTs), can be used as a suitable tool for targeted drug delivery. In this study, the physical chemistry properties of the interaction of the anti-cancer drug Lomustine with carbon nanotube (5,0) zigzag doped with iron or chromium atoms have been investigated. In the first step, the adsorption features, which is a key factor in the drug delivery system, has investigated to measure the efficiency of carbon nanotubes (5,0). In this regard, the density functional theory (DFT) method has used and the calculations have performed at the B3LYP/6-311G (d, p) theoretical level. To achieve the desired aim in this study, structural parameters such as adsorption energy, dipole moment, density of state plots, energy gap and the energies of molecular orbitals have calculated and studied. The results have shown that the orbital energy level was significantly decreased by adsorption of the drug on nanotubes doped with iron or chromium atoms. Other properties of this interaction such as chemical potential, chemical hardness and softness, and electrophilicity, also change significantly.

At first, inorganic powders including pine cone ash, micronized silica and alumina were coated with oleic and stearic acid in technical grade solvents including ethanol (96%) and toluene under heat treatment. Then, the different amounts of each coated powders and their mixture were used to modify the bitumen. Different properties of the modified bitumens including penetration rate, softening point, and the results of dynamic shear rheometer (DSR), bending beam rheometer (BBR), and multiple stress creep recovery (MSCR) tests were compared with the pure bitumen sample. The results showed that the penetration rate is increased with increasing of the percentage of the coated additives. In addition, the softening point of the pure bitumen sample has no significant change with addition of the coated powders. This phenomenon is an advantage in the modification of bitumen. The results of DSR test showed that the maximum total shear stress modulus (G*) at three different temperatures is related to the silica sample coated with oleic acid. The results of BBR test showed that the maximum creep hardness at -6 and -12°C is related to 4% silica coated with oleic acid and 2% pine cone ash coated with stearic acid, respectively. The MSCR test indicated that the maximum recovery percentage in a stress of 100 and 3200 Pa was observed for 2% silica coated with stearic acid and 4% pine cone ash coated with stearic acid, respectively

A novel graphene oxide/ zinc oxide nano composite was synthesized and employed for simple and sensitive pipette tip based micro solid phase extraction of ciprofloxacin from seawater and human blood plasma samples following by their determination by spectrophotometry. Several parameters affecting the suggested protocol were optimized, namely type and volume of eluent, amount of sorbent, sample volume, ionic strength of sample solution, and number of cycles of extraction and elution. The optimizations were performed by both response surface methodology and one variable at a time techniques. Analytical figures of merit were achieved as: detection limit; 0.17 µg/L, linear calibration curve in the range of 1.0-200.0 µg/L; and reproducibility (as RSD%) better than 5.6. Results for the application of the technique in seawater and human blood plasma showed that this analysis method can be applied for the determination of the analyte in complex real samples such as seawater and human successfully.

In this work, one-pot synthesis of dihydropyrano[2,3-c]pyrazole and pyrazolopyranopyrimidine derivatives from the reaction between aromatic aldehydes, ethyl acetoacetate, hydrazine hydrate, and malononitrile or barbituric acid in the presence of vitamin A as a heterogeneous, green and eco-friendly catalyst is discussed. mild reaction conditions, avoiding the use of any hazardous and toxic solvents, high yield, operational simplicity, simple work up without need to column chromatography are some of benefits present method in synthesis of this biologically compounds.In this work, one-pot synthesis of dihydropyrano[2,3-c]pyrazole and pyrazolopyranopyrimidine derivatives from the reaction between aromatic aldehydes, ethyl acetoacetate, hydrazine hydrate, and malononitrile or barbituric acid in the presence of vitamin A as a heterogeneous, green and eco-friendly catalyst is discussed. mild reaction conditions, avoiding the use of any hazardous and toxic solvents, high yield, operational simplicity, simple work up without need to column chromatography are some of benefits present method in synthesis of this biologically compounds.

Tetrazoles are an important class of nitrogen-rich heterocycles which have a wide range of applications in high energy materials, pharmaceutical industries, treatment of various disease, biochemistry, bioimaging, and photography. In this paper, Zr0.25Zn0.25Cu0.5Fe2O4 catalyst was first synthesized by two common combustion and hydrothermal methods and was then characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) methods. Furthermore, this catalyst has the magnetic properties. The catalytic activity of the Zr0.25Zn0.25Cu0.5Fe2O4 heterogeneous magnetic catalyst was investigated for the synthesis of a wide range of 5-substituted-1H-tetrazole derivatives via [3+2] cycloaddition of sodium azide with various nitriles in N,N-dimethylformamide at 120 °C. The main advantages of this method are high efficiency, simple methodology, easy work-up and catalyst reusability. Furthermore, this catalyst can be easily separated from the reaction mixture using an external magnet and reused for five cycles without a significant decrease in its catalytic activity.

In this research, the electron transfer rate of the anodic reaction of the lithium-air battery was theoretically investigated in the presence of the imidazolium-based dicationic ionic liquids (ILs), Cn(mim)22(NTF2), as an electrolyte. For this purpose, the electron transfer rate constant (ket) of the related reaction was calculated using Marcus' theory. Gibbs free energy of the reaction (ΔG0), reorganization energy (λ), and electron coupling energy (VRP) calculated using the density functional theory (DFT) method. All calculations performed using DFT with GGA/revPBE and B3LYP exchange-correlation functional and 6- 311++G** basis set, using NWchem software. Results show that the ket at the anode depends on the solvent dielectric constant. The longer alkyl chains in the ILs resulted in a decrease in dielectric constant and, consequently, a decrease in ket. Calculated ket values for dicationic ILs ranged from 1.312 to 1.416, which are higher values than those of mono-cationic ILs. The findings of this study are important because the ILs are green solvents with tunable properties.

Lithium - ion batteries (LIBs) are good alternative to traditional energy sources, which are considerably used in electronic devices. These sources have high energy density and long life. For this purpose, an attempt is made to design batteries based on nanostructures that have a significant voltage. In this study, the application of decaborane (B10H14) and its fluorinated derivatives in anode of Lithium-ion batteries is investigated using density functional theory (DFT) calculations. The results indicate that the cell voltage in decaborane (B10H14) is negative, which is unfavorable. One strategy to improve the function of decaborane is based on the substitution of hydrogen atoms in different positions with fluorine atoms. This can improve the cell function and increase the cell voltage remarkably to +1.10 Volt. This results might be useful for the design of novel inorganic-based anode materials for lithium-ion batteries. we hope the results provide meaningful insights for developing Lithium - ion batteries.

Carbon dots are spherical nanoparticles that behave differently from other carbon allotropes (carbon nanotubes, activated carbon, graphenes, and fullerenes) and have interesting and significant optoelectronic properties. Carbon dots have attracted a lot of attention due to their harmless elements in their structure (environmentally friendly), low toxicity, high and stable sensitivity, fast response and cheap price compared to other quantum nanoparticles.Conditions and synthetic methods of carbon dots have an essential role in their quality and will improve the properties of the final product. In this study, for the first time, modified carbon dots with active functional groups are synthesized in one step using the microwave method. The synthesized carbon dot was evaluated by instrumental techniques and the presence of nitrogen and oxygen groups in the surface and structure of the synthesized carbon dot was confirmed. The excitation wavelength of 365 nm has a strong emission in the wavelength of about 436 nm. The size of the synthesized carbon dot is about 20 nanometers. Using devices such as UV-Vis, scanning electron microscope (SEM) and transient electron microscopy (TEM), the presence of gold nanoparticles synthesized by red apple peel extract was investigated.The results show that gold nanoparticles prepared using red apple peel extract have a size of 13-20 nm, spherical morphology and good dispersion that are stable for a long time.